A. Field of the Invention
This invention relates to the field of flexible web handling and converting; especially the handling of webs supplied on long rolls known as bobbins. More specifically, this invention relates to a method and apparatus for reducing, capturing and disposing of the waste start up web of paper in high-speed manufacturing procedures which involve a converting step, e.g. laser perforation or the like.
B. Description of the Related Art
It is customary in the art, e.g. of cigarette manufacturing, to perform converting functions on lengthy rolls of paper provided in bobbins. Cigarettes use substantial amounts of paper in their production--as a wrapper, to enclose filter tow material as filters, and to tip filters onto columns of wrapped tobacco, to name a few exemplary uses.
Converting as used herein refers to a function such as perforation, either mechanically or by thermal energy transfer (e.g. focused laser energy or the like), printing, embossing, slitting, or other comparable functions on paper, films, or other flexible webs. For ease of illustration; however, a single embodiment will generally be referred to in the specification (laser perforation of paper), but one of skill in the art may easily see where this disclosure may have a wide range of applications. The protection afforded by this application should therefore be measured with reference to the appended claims and not the examples herein.
Each of the following cited patents are hereby incorporated in their entireties by reference. For ease of reference, they are broken up into topical sections. Kindly note that what follows is not meant to be an exhaustive description of the prior art, rather, a short description for assistance in understanding the prior art.
1. Conversion
Conversion of materials includes a variety of functions--printing, perforating, embossing, slitting, and the like.
U.S. Pat. No. 3,226,527 discloses the perforation of sheet materials by passing a laser beam over the sheet materials and interrupting the beam. Such an apparatus feeds the web from a roll as seen in FIG. 1 of that patent.
U.S. Pat. Nos. 3,965,327 and 4,049,945 disclose the cutting of a moving web of material by pivoting mirrors to trace and cut a predetermined pattern.
U.S. Pat. No. 4,118,619 (Re. 31,478) discloses a beam chopping device for converting a continuous beam into a series of scanning impulses with a series of annular rings which direct the beam onto a moving web of paper.
U.S. Pat. No. 4,121,595 discloses the perforation of wrapping paper by laser, monitoring the permeability of the wrapper, and adjusting the intensity of the laser in response to deviations from a desired value.
U.S. Pat. No. 4,265,254 discloses the perforation of smoking article wrappers on an advancing path by moving a reflector in conjunction with an energizer for the laser source to provide a plurality of holes from one source.
U.S. Pat. No. 4,302,654 discloses the perforation of cigarette tipping paper by placing a laser source inside of a cylindrical rotating roller mask having apertures and passing the paper over the surface of the mask.
A large number of other patents disclose various perforation means and apparatus, including U.S. Pat. No. 4,378,480 (beam chopping for web perforation); U.S. Pat. No. 4,404,452 (beam chopping with light reflective/transmission portions on rotatable assembly for web perforation); U.S. Pat. No. 4,404,454 (forming pulsed beams from a single beam); U.S. Pat. No. 4,410,785 (pair of laser beams derived from laser beam to provide perforation uniformity); U.S. Pat. No. 4,439,663 (forming matrix of beams from continuous focused laser beam); U.S. Pat. No. 4,916,272 (split laser beam reconverged); U.S. Pat. No. 4,767,909 (pulsed laser beam split; web perforated by focused beams); U.S. Pat. No. 5,060,668 (pulsed laser directed on bicomponent lens having two separate foci to perforate paper); U.S. Pat. No. 5,092,350 (laser directed by acousto-optical deflector and splitter to produce two parallel perforation tracks); U.S. Pat. Nos. 5,210,390 and 5,403,990(continuous convergent beam deflected by rotating polygon mirror, split by beam splitters, and refocused in a plurality of locations on traveling web)and U.S. Pat. No. 5,404,889 (movable focusing head focuses beam on traveling cigarette wrapper).
2. Web Transport
It is known to wrap bundles and packages of items using material fed from rolls, either as a part of external packaging, or a part of the product itself. U.S. Pat. No. 3,589,100 discloses an apparatus which provides a first and second web of heat sealable material, one fed from an upper roll, one fed from a lower roll, which are heat sealable to form a package exterior.
U.S. Pat. No. 3,634,172 discloses an apparatus for holding two abutting tape ends in place and applying a segment of splicing material across their junction.
U.S. Pat. Nos. 3,743,197 and 3,764,085 disclose a method of and apparatus for handling material. These disclosures are directed to a threading device which slits a web of film supplied from a supply source, and uses this slit to form a leader strip which is then used in conjunction with pneumatic moving threadup devices to feed a web onto a windup roll.
U.S. Pat. No. 4,065,918 discloses a winding machine for automatically winding a sheet of material into a roll and applying a leader tape to the roll. Once a desired length is wound onto a roll, the sheet material is severed, and a tab is optionally formed by folding back the sheet material.
U.S. Pat. No. 4,322,043 discloses a web transport apparatus which is closely related to the present invention. Multiple webs are capable of being mounted on a web treatment apparatus and multiple receiving reels are provided. The web being treated, e.g. by laser, is on the active path, while the web change results in a standby web in a storage support structure. As the treated web finishes, a lateral transport means shifts the standby web into the active path, leaving the machine idle for only a brief period. This disclosure is incorporated herein by reference.
Likewise, U.S. Pat. No. 4,346,284 discloses an apparatus which is closely related to the present invention. Two independent transport paths are provided for a web of material. Thus, the treating device (e.g. a laser) is substantially constantly treating a web and the machine is never idle, except for the period required to redirect the beam and accelerate the web to full processing speed. This disclosure too is incorporated herein by reference.
U.S. Pat. No. 4,475,830 discloses a spliceless ribbon structure having a leader and trailer, e.g. for use as a transferrable ink layer ribbon for impact printing. A leader and trailer formed from double sided adhesive encapsulate the ink web at the beginning and end of the web. The ink web is fed from a master roll of ribbon stock to smaller hubs.
U.S. Pat. Nos. 4,894,674 and 5,015,089 disclose a bulk film loader for loading film cassettes from a bulk quantity of film. The film is transferred within a casing from a cartridge onto a camera film feed spool. A manually operated guillotine is provided to sever the strips, and a roll of adhesive leaders is provided.
U.S. Pat. No. 4,916,272 discloses a web roll, guide rollers, a drum for perforating, guide rollers, a guide block and a takeup roll for perforating a paper web supplied on a bobbin.
Finally, U.S. Pat. No. 5,467,676 discloses an automatic roll wrapper removing apparatus and method. Paper rolls are supplied in bobbins which are wrapped in a protective wrapper. The wrapper generally should be removed before use, and this disclosure relates to a method and apparatus for unwrapping these rolls by cutting the outer wrapper automatically.
3. Control of Perforation
Many efforts have been made to attempt to control the perforation of the substrate while it is being worked upon during normal operational speeds.
U.S. Pat. No. 4,218,606 discloses the maintaining of a constant porosity on a workpiece subjected to varying speeds by adjusting the focus point of the laser beam to create larger or smaller holes in response to porosity feedback.
U.S. Pat. No. 4,568,815 discloses the control of a laser perforator. The speed of the workpiece is detected, and the laser duty cycle is gated to provide uniform perforations.
U.S. Pat. No. 5,259,401 discloses the control of the intensity of radiation and the length of pulses in response to variations in the speed of advancement of the web past a perforator. Additional control, such as control of the intensity of radiation based on permeability, is also disclosed.
U.S. Pat. No. 5,341,824 discloses a highly sophisticated control system for a high speed perforator on a tipping paper line. Electro-optical detectors sense the porosity and control the perforation based upon a calculated pressure drop.
Finally, U.S. Pat. No. 5,367,144 discloses a comparator for determining the porosity of paper being produced by a laser perforator by comparing the paper perforated to a standard in a simultaneously applied suction unit. This is said to overcome variances in the pressure in the unit over time.
4. Other Known Art--Generally
In present operation, the rolls of material are generally unwound, the conversion function is performed upon the paper, and the new bobbin wound up on a new bobbin core.
However, substantial losses are incurred during the conversion at conversion startup. For example, the web speed is constantly changing as it ramps up to operating speed and it has been heretofore virtually impossible to control the amount of laser energy and perforation applied. Conventional rewinders cause the loss of about 25 meters of paper at startup.
This wasted paper is generally wound about the core of the rewinder, and an adhesive tab inserted into the bobbin at the point where the perforation or other conversion is within acceptable limits or of sufficient quality to be inserted into consumer or other goods, usually at a thickness of about 8 mm around the core; often as much as 12-14 mm. This is a substantial waste of paper (up to 125 meters) which must be carted around to an appropriate manufacturing facility in order that the good paper can be incorporated into consumer goods, leading to wasted space, fuel, etc.
Additionally, a conversion facility or manufacturing facility operating at large capacity generates a large volume of waste. It would be useful to reduce the labor involved in handling this waste.
No known equipment or publications address methods or apparatuses for solving this waste of a substantial length of paper. A solution to this problem is needed.